In 2012 the U.S. State Department warned travelers about the dangers of visiting 33 countries, spanning from Algeria to Yemen. Some warnings simply suggest exercising caution while others are “no go” warnings, baldly stating that you shouldn’t visit.

Since the new year, the State Department has issued six travel warnings: to El Salvador, Algeria, Mali, Niger, Kenya, and Libya. But a brighter note, the agency currently has only one active travel alert, about the dangers of South Pacific cyclone season. That’s a bit of good news for the 65 million U.S. citizens who travel internationally and the 6.3 million who live abroad.

The updates got us wondering about a few things: What the difference is between a warning and an alert; who decides when to issue a government travel advisory; and how such decisions are made.

For answers, we spoke with Brendan O'Brien, director of American Citizens Services in Washington, D.C., a section inside the Bureau of Consular Affairs that is ultimately responsible for the country risk assessments that are posted on the State Department’s website (travel.state.gov).

Warnings and alerts are generated from several sources, says O'Brien. Most information comes from field officers, and their reports are combined with intelligence filtered from various governmental agencies by the State Department's Bureau of Diplomatic Security. The Citizen Services team coordinates the overall process, and O'Brien has to sign off on every travel warning before it's publicized.

"But alerts and warnings are not usually a Washington, D.C.-top-down-sort-of-thing," he adds. "The genesis usually comes instead from embassies and consulates overseas, who have contacts in law enforcement, government and media on the ground."

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Travel Warnings**

The best known of the advisories is the “travel warning,” which tends to be open-ended. O’Brien explains that travel warnings are customarily reserved for places that will probably be dangerous for Americans for a while.

Exhibit A: The State Department recently renewed its warning about travel to Mali, in light of recent events. The U.S. government also commonly issues warnings against travel to countries where it has a reduced ability to help citizens if they get into trouble, such as Iran, where the U.S. has no diplomatic representation. Warnings are reviewed every six months.

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Travel Alerts**

So-called “travel alerts,” on the other hand, tend to be time-limited, aimed at raising awareness about short-term problems, from something as specific as a coup to something more general, like typhoon season in the Pacific. Alerts are issued for a specified period, at the end of which time they are reviewed and often rescinded.

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Emergency Messages**

Importantly, we should mention the most dramatic type of travel advisory, which is also one that you may not encounter until the last minute, namely, the “message.” Unlike alerts and warnings, messages—sometimes called emergency messages or security messages—are often issued by an embassy or consular office rather than the State Department itself and are about immediate, short-term security or emergency concerns, such as recent protests in Bolivia.

“If lives could be in immediate danger, the embassy or consulate has discretion to send out information without waiting to clear it from Washington," says O'Brien, who was previously the consular chief in Kabul, Afghanistan, and American Citizen Services chief in Bogotá, Colombia. "It’s our mission to avoid bureaucracy getting in way of citizen safety.

Are the advisories politicized? O’Brien laughs and says no. “The Bureau is insulated from external pressures, foreign or domestic, and any complaints are dealt with by the department’s Consular Affairs Press Division and by the embassy desk in the relevant country.”

O’Brien acknowledged that sometimes there are differences in how the U.S. and other governments make judgments about safety and that evaluations evolve as information becomes available. He says that his office is required to prepare travel alerts and warnings according to standardized guidelines spelled out in the Foreign Affairs Manual. The government must also follow the "no double standard policy," which means officers are required to disseminate any important security threat information if the threat could apply to citizens. Other arms of the U.S. government, such as the Department of Defense, must comply with the policy, too. If they hear about a threat to Americans overseas, they’re statutorily required to let the relevant embassy know. So while O’Brien insisted that accuracy is his team’s number one job, this reporter couldn’t help but infer that these commandments to share any bit of potentially relevant information may sometimes lead government officials to err on the side of over-sharing.

Any American traveling internationally, even to a supposedly safe place, should register with the State Department via its Smart Traveler Enrollment Program (STEP), which sends breaking alerts and information to travelers in case of a crisis by text or e-mail. Free iPhone and Android apps make it easy to receive the warnings, alerts, and messages on the fly.

Oh, and in case you were wondering, other countries do, from time to time, issue travel warnings for their citizens traveling to certain areas of the U.S. In the 1990s, for example, when there was a rash of people being murdered after they had rented cars in Miami, other countries warned their citizens about travel to the city.

Another mystery, solved! Write or tweet us_ (@CNTraveler) _if you have a travel mystery you're hoping to clear up.